I would start with Beeman air gun co. They own the Marksman line of air guns (See the link below) or go online and look up "air gun repair" and locate someone near you to repair the rifle. Or see the link #2 below.
Contact the maker for a replacement manual
First let me explain the relationship of air gun manufactures. Very often air gun companies make air guns for other companies using the new air gun company name. Several air gun companies manufacture air guns under different brand names. Today Beeman owns Marksman air guns. I believe your Marksman 0035 was made by Norica "Of Spain" for sale through Beeman. Your rifle "Marksman 0035", is rated at about 700 FPS. This same rifle is also known as a "Beeman GS700". I picked one up off craigslist a month ago. With 7.9 grain pellets mine shoots at 550 FPS This is good to know. Air gun companies rate their own air guns as far as FPS. Usually they are somewhat over rated. Super lightweight pellets fly very fast but are not as accurate as a heavy weighted pellet that flies straighter and is not as affected by crosswind.
200 or so ------------------------------------------------- The slowest BB gun ( NOT Airsoft or Pellet gun) that I know of is the Marksman 1010, it is rated at 200 FPS. The fastest BB gun I could find is the Crosman 2100 that is rated at 755 FPS. This gives you an average of 477.5 FPS Pellet guns and rifles can attain much faster speeds.
I would search the web for "Air gun Repair" and locate a shop near you that can repair it or see the link below for shops that repair air guns.
Oh, dude, loading pellets into a Marksman Repeater is like, super easy. You just pull back the bolt, drop a pellet into the chamber, push the bolt forward, and you're good to go. It's like loading a Nerf gun, but with more potential for accidentally shooting your eye out.
It depends on the model and the caliber of the Pellet gun.
The Marksman Model 740 .177 pellet rifle. It has a wood-patterned plastic stock. It is a single shot rifle that folds in the middle for cocking and loading. The safety auto-enables after every trigger pull. You must cock and reset the safety
I think you mean pellet gun. That is a gun that fires a small lead pellet but does not use gun powder. It uses compressed air or compressed gasses to push the pellet.
A pellet gun is not adequate for protection, and will get you arrested.
Any pellet gun should be handled like a real firearm. Yes you can be killed with a pellet gun under the right circumstances.
It all depends on the model and who made the pellet gun. I suggest that you re-post the queston with the model and make of the pellet gun to get an answer.